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A gate sequence of single-qubit transformations may be condensed into a single microwave pulse that maps a qubit from an initialized state directly into the desired state of the composite transformation. Here, machine learning is used to…

Quantum Physics · Physics 2025-07-18 Jaden Nola , Uriah Sanchez , Anusha Krishna Murthy , Elizabeth Behrman , James Steck

In this paper, we present the experimental realization of multi-qubit gates $% \Lambda_n(not) $ in macroscopic ensemble of three-qubit and four-qubit molecules. Instead of depending heavily on the two-bit universal gate, which served as the…

Quantum Physics · Physics 2009-11-06 J. F. Du , M. J. Shi , J. H. Wu , X. Y. Zhou , R. D. Han

Nonadiabatic holonomic quantum computation (NHQC) has attracted significant attention due to its fast evolution and the geometric nature induced resilience to local noises. However, its long operation time and complex physical…

Quantum Physics · Physics 2022-03-23 Yan Liang , Pu Shen , Tao Chen , Zheng-Yuan Xue

Frequency-encoded quantum information offers intriguing opportunities for quantum communications and networking, with the quantum frequency processor paradigm -- based on electro-optic phase modulators and Fourier-transform pulse shapers --…

The present era of quantum processors with hundreds to thousands of noisy qubits has sparked interest in understanding the computational power of these devices and how to leverage it to solve practically relevant problems. For applications…

Quantum Physics · Physics 2026-04-15 Victor Martinez , Omar Fawzi , Daniel Stilck França

Quantum noise in real-world devices poses a significant challenge in achieving practical quantum advantage, since accurately compiled and executed circuits are typically deep and highly susceptible to decoherence. To facilitate the…

Quantum Physics · Physics 2025-06-13 Yuchen Guo , Shuo Yang

We present pulse sequences for two-qubit gates acting on encoded qubits for exchange-only quantum computation. Previous work finding such sequences has always required numerical methods due to the large search space of unitary operators…

Quantum Physics · Physics 2014-07-23 Daniel Zeuch , R. Cipri , N. E. Bonesteel

Quantum gates based on geometric phases possess intrinsic noise-resilience features and therefore attract much attention. However, the implementations of previous geometric quantum computation typically require a long pulse time of gates.…

Quantum Physics · Physics 2022-10-10 Zhuang Ma , Jianwen Xu , Tao Chen , Yu Zhang , Wen Zheng , Dong Lan , Zheng-Yuan Xue , Xinsheng Tan , Yang Yu

Two-qubit gate performance is vital for scaling up ion-trap quantum computing. Optimized quantum control is needed to achieve reductions in gate-time and gate error-rate. We describe two-qubit gates with addressed Raman beams within a…

The creation of composite quantum gates that implement quantum response functions $\hat{U}(\theta)$ dependent on some parameter of interest $\theta$ is often more of an art than a science. Through inspired design, a sequence of $L$…

Quantum Physics · Physics 2018-02-02 Guang Hao Low , Theodore J. Yoder , Isaac L. Chuang

Refocusing of a quantum system in NMR and quantum information processing can be achieved by application of short pulses according to the methods of spin echo and dynamical decoupling. However, these methods are strongly limited by the…

Quantum Physics · Physics 2016-02-29 Imdad S. B. Sardharwalla , Toby S. Cubitt , Aram W. Harrow , Noah Linden

Quantum process tomography of each directly implementable quantum gate used in the IBM quantum processors is performed to compute gate error in order to check viability of complex quantum operations in the superconductivity-based quantum…

Quantum Physics · Physics 2022-06-07 Abhishek Shukla , Mitali Sisodia , Anirban Pathak

We introduce flexible high-fidelity passband (PB) composite pulse sequences constructed by concatenation of recently derived arbitrarily large and arbitrarily accurate broadband $\mathcal{B}$ and narrowband $\mathcal{N}$ composite…

Quantum Physics · Physics 2014-01-08 Elica Kyoseva , Nikolay V. Vitanov

We employ pulse shaping to abate single-qubit gate errors arising from the weak anharmonicity of transmon superconducting qubits. By applying shaped pulses to both quadratures of rotation, a phase error induced by the presence of higher…

Mesoscale and Nanoscale Physics · Physics 2012-03-15 J. M. Chow , L. DiCarlo , J. M. Gambetta , F. Motzoi , L. Frunzio , S. M. Girvin , R. J. Schoelkopf

Virtual $Z$ gates have become integral for implementing fast, high-fidelity single-qubit operations. However, virtual $Z$ gates require that the system's two-qubit gates are microwave-activated or normalise the single-qubit $Z$…

Quantum Physics · Physics 2025-09-18 Christopher K. Long , Crispin H. W. Barnes

We introduce universal broadband composite pulse sequences for robust high-fidelity population inversion in two-state quantum systems, which compensate deviations in any experimental parameter (e.g. pulse amplitude, pulse duration, detuning…

Quantum Physics · Physics 2015-06-19 Genko T. Genov , Daniel Schraft , Thomas Halfmann , Nikolay V. Vitanov

Quantum computation holds the promise of solving computational problems which are believed to be classically intractable. However, in practice, quantum devices are still limited by their relatively short coherence times and imperfect…

Quantum Physics · Physics 2023-12-22 Sagar Silva Pratapsi , Diogo Cruz

Quantum computing is on the cusp of reality with Noisy Intermediate-Scale Quantum (NISQ) machines currently under development and testing. Some of the most promising algorithms for these machines are variational algorithms that employ…

Advances in development of quantum computing processors brought ample opportunities to test the performance of various quantum algorithms with practical implementations. In this paper we report on implementations of quantum compression…

Quantum Physics · Physics 2022-09-22 Matej Pivoluska , Martin Plesch

Spins based in silicon provide one of the most promising architectures for quantum computing. Quantum dots are an inherently scalable technology. Here, we combine these two concepts into a workable design for a silicon-germanium quantum…